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Topic: Color Space: sRGB vs AdobeRGB (Read 12244 times)

I shoot for my University Yearbook and the publishing company recently requested that we begin shooting in AdobeRGB color space. I don't really understand what the difference in the 2 is and why they would have us change it, not that is difficult to change back and forth. I was just curious if anyone may know why they requested this or if Adobe color space has an advantage or something over sRGB?

When you have (for example) a JPEG file, each pixel is characterised by 'red', 'green' and 'blue' numbers.

The colour-space defines how these numbers map to an actual colour - it is what allows you to determine that { 90, 90, 10 } represents a particular shade of 'burnt-yellow', for example. sRGB and AdobeRGB are just different ways of mapping those numbers to actual colours. AdobeRGB is a mapping that can encompassed a much broader range of colours - including colours that can not be represented in sRGB at all.

Every method you have for displaying your images will have some limitations on the colour space. For example, a printer may be limited by the ink colours that it has, and a monitor by the particular characteristics of its phosphor or LCD filters.

Generally, it is easier to display sRGB images - partly because the smaller range of colours means that more output format can show the image as you intended, and partly because for historical reasons sRGB is widely used. However, some output formats (or image processing software) may be able to use a broader range of colours than sRGB can represented - in which case using AdobeRGB is a better bet.

Note that if you shoot in RAW, the CR2 files have a colour space that is defined by the colour-filter array on the camera sensor - the broadest colour space possible, but specific to any given make/model of camera. However, when you process the RAW files you can choose to re-map this to sRGB, AdobeRGB or any other space that you choose.

When you have (for example) a JPEG file, each pixel is characterised by 'red', 'green' and 'blue' numbers.

The colour-space defines how these numbers map to an actual colour - it is what allows you to determine that { 90, 90, 10 } represents a particular shade of 'burnt-yellow', for example. sRGB and AdobeRGB are just different ways of mapping those numbers to actual colours. AdobeRGB is a mapping that can encompassed a much broader range of colours - including colours that can not be represented in sRGB at all.

Every method you have for displaying your images will have some limitations on the colour space. For example, a printer may be limited by the ink colours that it has, and a monitor by the particular characteristics of its phosphor or LCD filters.

Generally, it is easier to display sRGB images - partly because the smaller range of colours means that more output format can show the image as you intended, and partly because for historical reasons sRGB is widely used. However, some output formats (or image processing software) may be able to use a broader range of colours than sRGB can represented - in which case using AdobeRGB is a better bet.

Note that if you shoot in RAW, the CR2 files have a colour space that is defined by the colour-filter array on the camera sensor - the broadest colour space possible, but specific to any given make/model of camera. However, when you process the RAW files you can choose to re-map this to sRGB, AdobeRGB or any other space that you choose.

Interesting. I always shoot in Raw exclusively on my 5D II and 1Ds III (are there differrences on these two sensors in what type of color they can receive in Raw on the sensor?). My main question is this: Would it not make sense to always shoot in AdobeRGB? As I understand it, you can always change the colorspace in post-processing in program such as CS or Lightroom, thus giving you the best, and enabling you to use it the way you want, as opposed to the opposite where you shoot in sRGB because you wanted to produce for web, and then find out that you would like to do more with the picture (apart from the extra space the AdobeRGB takes, which is not relevant for me)?

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Shooting RAW gives you the full options in post so that gives you the most flexibility and future proofing options.

What is important to realise is that there is still only 255 steps between colours in either colour space (8bit jpeg), adobe rgb having more of a step between each colour. This is only important when you tweak the curves and potentially stretch and get banding in areas like sky. This is why capturing raw, converting to 16 bit depth and choosing srgb or adobe rgb to edit is best, choosing which one really depends on the final display (monitor or print).

Shooting RAW gives you the full options in post so that gives you the most flexibility and future proofing options.

What is important to realise is that there is still only 255 steps between colours in either colour space (8bit jpeg), adobe rgb having more of a step between each colour. This is only important when you tweak the curves and potentially stretch and get banding in areas like sky. This is why capturing raw, converting to 16 bit depth and choosing srgb or adobe rgb to edit is best, choosing which one really depends on the final display (monitor or print).

Just my 2p!

So are you saying that it does not matter if my cameras are set on sRGB or AdobeRGB, because I am shooting in Raw? and that everything can be fixed in post? While opposed to Jpg. where the setting on the camera is more limiting wheter you have your camera set on sRGB or AdobeRGB?

So are you saying that it does not matter if my cameras are set on sRGB or AdobeRGB, because I am shooting in Raw? and that everything can be fixed in post? While opposed to Jpg. where the setting on the camera is more limiting wheter you have your camera set on sRGB or AdobeRGB?

That's how it works, a raw file doesn't have a color profile as such and you can also fix white balance later with raw. When I say "as such" the camera can still embed the camera settings that applications like LR will use by default, but changing it later doesn't have any implications.

I guess the easy way to think of it is that raw is a capture of what the camera sensor has captured at that point in time and all that will ever be available even in a 100 years. Meanwhile in that 100 years monitors and printers will probably have progressed much further and today's gamuts will be considered obsolete.

So are you saying that it does not matter if my cameras are set on sRGB or AdobeRGB, because I am shooting in Raw? and that everything can be fixed in post? While opposed to Jpg. where the setting on the camera is more limiting wheter you have your camera set on sRGB or AdobeRGB?

That's how it works, a raw file doesn't have a color profile as such and you can also fix white balance later with raw. When I say "as such" the camera can still embed the camera settings that applications like LR will use by default, but changing it later doesn't have any implications.

I guess the easy way to think of it is that raw is a capture of what the camera sensor has captured at that point in time and all that will ever be available even in a 100 years. Meanwhile in that 100 years monitors and printers will probably have progressed much further and today's gamuts will be considered obsolete.

i understand the 1st chart.. but what are 2nd and 3rd if you could expand a little more?

On the charts Johan posted the D50/D65 is for different sources of illumination. Check out the following page, I'd probably just stick with the introduction and table down the bottom unless your math is a lot better than mine

The AdobeRGB(1998) Specification, May 2005 (PDF). Seems they like to stick with the original release year even though there have been revisions since, although after a very quick look it looks like the revisions have only clarified things and not changed basic operation. Anyway don't forget it's dealing with changes in basic printing technology, I don't know a great deal about that area but can't remember reading about any amazing new processes any time recently. I'm guessing it was more about the era that digital typesetting became 'serious'.